Mobile Detecting problem using adb

After installation of android SDK open terminal go to directory of your platform-tools using cd command on terminal after connect your android mobile to system through USB cable before connecting check debug is enable or not in your phone, how check enable or not go to setting on your phone developer options tick debug option if disable. Following command type for detecting  your mobile into your system

$adb devices 

Normally it will your phone some situations it will not detect, type following commands

$adb kill-server

it will kill server of adb

$adb start-server

$adb devices 

Now almost it will detect still it not detect do following steps

$cd /etc/udev/rules.d/

$sudo vi 51-android.rules

After opening vi editor goto last line of script type following line

SUBSYSTEM="usb",ATTR{idVendor}=="vendor id", MODE="0666"

for finding vendor of mobile type lsusb command after typing above line save and quit (:wq)
http://developer.android.com/tools/device.html

$sudo chmod a+rx /etc/udev/rules.d/51-android.rules 

$service udev restart 

$adb kill-server

Now try,

$adb start-server

$adb devices 

Hopefully it will detect still it not detect follow following procedure
First  open new  terminal

$cd  ~/.android/

$vi adb_usb.ini

there write vendor id of your phone next save file

$adb kill-server

$adb start-server

$adb devices




Now it detected successfully for me try your self